In California, you may pass the visual, but I highly doubt you'd pass the sniff check if you have a 1999 or older CR-V (tailpipe tests aren't required for 2000 and newer vehicles). There is so much less catalyst material in a high flow cat (most of it "burns off" with use, so it's basically a straight pipe). According to a few posts I've read on other forums, there may be a small window of opportunity to pass, if your high flow cat is fairly new (and brave enough to try). YMMV. I have a high flow cat in my Civic. The smell of gasoline is so prevalent, it's a dead giveaway.